Fix `rainbow-mode' setup

README.org

@@ -5940,23 +5940,19 @@ narrowed."
 :CUSTOM_ID: sec:rainbow-mode
 :END:
 
-Listing [[lst:enable-rainbow-mode]] enables =rainbow-mode= to colorize color codes
+Listing [[lst:setup-rainbow-mode]] configures =rainbow-mode= to colorize color codes
 and names in buffers for debugging.
 
-#+caption[Enable =rainbow-mode=]:
-#+caption: Enable =rainbow-mode=.
-#+name: lst:enable-rainbow-mode
+#+caption[Setup =rainbow-mode=]:
+#+caption: Setup =rainbow-mode=.
+#+name: lst:setup-rainbow-mode
 #+begin_src emacs-lisp -n :results silent
-(when (and (ensure-package-installation 'rainbow-mode)
-           (fboundp 'rainbow-mode))
-  (setopt rainbow-x-colors-major-mode-list '(c++-mode
-                                             c-mode
-                                             emacs-lisp-mode
-                                             inferior-emacs-lisp-mode
-                                             lisp-interaction-mode
-                                             org-mode
-                                             python-mode))
-  (rainbow-mode +1))
+(when (ensure-package-installation 'rainbow-mode)
+  (setopt rainbow-x-colors-major-mode-list
+          (list 'c++-mode 'c-mode 'emacs-lisp-mode 'inferior-emacs-lisp-mode
+                'lisp-interaction-mode 'org-mode 'python-mode))
+  (dolist (symbol '(emacs-lisp-mode-hook python-mode-hook))
+    (add-hook symbol #'rainbow-mode)))
 #+end_src
 
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